The invention relates to evaporable foam patterns used in lost foam casting processes. The invention also relates to methods for manufacturing such foam patterns.
Foam pattern assembly portions are typically injection molded. A conventional mold defines a mold cavity and has therein a passageway communicating with the mold cavity through a wall that will form a glue surface on the resultant foam pattern portion. A fill gun is inserted into the passageway and foam particles are injected into the mold cavity to form the pattern portion. If the end of the fill gun is not flush with the wall forming the glue surface, i.e., if the fill gun backs slightly out of the mold, the result is, on the pattern portion, a boss extending outwardly from the glue surface and into the passageway. This boss must be trimmed off before the glue surface of the foam pattern portion is glued to another pattern portion.